Low-Carbohydrate VS Low-Fat Diets For Type 2 Diabetes

Two of the biggest health issues facing society today are overweight/obesity and type 2 diabetes. Despite therapeutic advances, prevalence of both conditions continue to soar. This suggests more effective treatment strategies are required to reverse the trend.

Background

Weight issues and type 2 diabetes often go hand-in-hand, with both having a contributing factor of blood glucose dysregulation. However, what is still up for debate is the impact of different ratio macro-nutrient diets on factors related to obesity and type 2 diabetes.

One particular diet continues to be an area of interest for type 2 diabetes – a low-carbohydrate diet. But these diets can often be high in saturated fat, which is a concern in regards to cardiovascular disease (CVD) risk.

Researchers wanted to explore the impact of a low-carbohydrate, high unsaturated fat diet on glycaemic control, weight and other CVD risk factors, compared a low-fat diet.

The study

A 2 year randomised control trial was designed. Inclusion criteria included age 35-68 years old with type 2 diabetes (T2D), a HbA1c level of ≥7.0% and/or taking diabetes medication, and a BMI of 26-45kg/m².

115 adults with type 2 diabetes were randomised into one of two groups. Both groups had an energy-matched, hypocaloric diet combined with exercise.

The low-carbohydrate diet (LC) had a breakdown of 14% carbohydrate, 28% protein and 58% fat. The high-carbohydrate (HC) diet consisted of 53% carbohydrate, 17% protein and 30% fat. Saturated fat was restricted to <10% in both groups.

Outcomes that were measured included:

HbA1c

Glycaemic variability

Anti-glycaemic medication effect score

Weight

Body composition, including fat mass

CVD risk factors

Renal risk factors

The findings

61 participants completed the full 2 years. Weight loss, body fat, blood pressure, HbA1c and fasting glucose were all similar between the groups, with no significant difference noted.

The LC group lost an average of 6.8kg, and the HC group lost an average of 6.6kg. HbA1c reduced by 0.6 in the LC group and 0.9 in the HC group.

Compared to the HC group, LC had a greater reduction in diabetes medication use, glycaemic variability and triglycerides. LC also maintained the HDL levels, but experience reduction in LDL and other risk factors for CVD. There was no evidence of adverse renal effects in the LC group.

Conclusions

Both groups experienced a significant reduction in overall weight, body fat mass and HbA1c levels over the 2 year period. There was also a similar reduction in blood pressure.

However, the LC group sustained greater reduction in diabetes medication use, saw improvements in blood glucose stability and blood lipid profile. Furthermore, there was no evidence of adverse renal effects.

This suggests that a low-carbohydrate, high-unsaturated fat diet may be more effective at managing T2D compared to a low-fat, high-carbohydrate diet.